1. Field of the Invention
The present invention relates to a battery accommodation casing for accommodating a laminate-sheathed cell, a battery module, and an assembled battery.
2. Description of the Related Art
In recent years, from a viewpoint of weight saving, a cell sheathed with laminate films or a laminate-sheathed cell has gained attention as a power source of an electric vehicle (EV) powered by electricity or of a hybrid electric vehicle (HEV) in which an engine and a motor are combined.
The laminate-sheathed cell is generally provided with flexible laminate films, and a power generating element is sealed by thermal adhesion of the outer peripheries of the laminate films. Further, the laminate-sheathed cell is provided with electrode leads. One end of each electrode lead is electrically connected to the power generating element and the other end of each electrode lead protrudes the outside of the laminate films (see Japanese Patent Application Laid-Open No. 2001-345081). In Japanese Patent Application Laid-Open No. 2001-345081, a gas release mechanism is also described. When gas generated within the cell reaches a predetermined pressure, this mechanism opens and releases gas to the outside.
Where the laminate-sheathed cell is used as a power source of an EV or a HEV, it is required to prevent corrosion of the laminate film over a long period of time to maintain a long life of the cell. In order to do so, it is considered to contain the laminate-sheathed cell in a battery accommodation casing in a hermetically sealed manner to seal out moisture.